Measurements

Area - Area of a pentagon
Area - Area of a hexagon

By the end of the lesson, the learner should be able to:
- Define a regular pentagon
- Draw a regular pentagon and divide it into triangles
- Calculate the area of a regular pentagon

In groups, learners are guided to:
- Draw a regular pentagon of sides 4 cm using protractor (108° angles)
- Join vertices to the centre to form triangles
- Determine the height of one triangle
- Calculate area of one triangle then multiply by number of triangles
- Use alternative formula: ½ × perimeter × perpendicular height

How do we find the area of a pentagon?

- Master Mathematics Grade 9 pg. 85
- Rulers and protractors
- Compasses
- Graph paper
- Charts showing pentagons
- Compasses and rulers
- Protractors
- Manila paper
- Digital devices

- Observation - Oral questions - Written assignments

Measurements

Area - Surface area of triangular prisms
Area - Surface area of rectangular prisms

By the end of the lesson, the learner should be able to:
- Identify triangular prisms
- Sketch nets of triangular prisms
- Calculate surface area of triangular prisms

In groups, learners are guided to:
- Identify differences between triangular and rectangular prisms
- Sketch nets of triangular prisms
- Identify all faces from the net
- Calculate area of each face
- Add all areas to get total surface area

How do we find the surface area of a triangular prism?

- Master Mathematics Grade 9 pg. 85
- Models of prisms
- Graph paper
- Rulers
- Reference materials
- Cuboid models
- Manila paper
- Scissors
- Calculators

- Observation - Oral questions - Written assignments

Measurements

Area - Surface area of pyramids
Area - Surface area of square and rectangular pyramids

By the end of the lesson, the learner should be able to:
- Define different types of pyramids
- Sketch nets of pyramids
- Calculate surface area of triangular-based pyramids

In groups, learners are guided to:
- Make pyramid shapes using sticks or straws
- Count faces of different pyramids
- Sketch nets showing base and triangular faces
- Calculate area of base
- Calculate area of all triangular faces
- Add to get total surface area

How do we find the surface area of a pyramid?

- Master Mathematics Grade 9 pg. 85
- Sticks/straws
- Graph paper
- Protractors
- Reference books
- Calculators
- Pyramid models
- Charts

- Observation - Oral questions - Written assignments

Measurements

Area - Area of sectors of circles
Area - Area of segments of circles

By the end of the lesson, the learner should be able to:
- Define a sector of a circle
- Distinguish between major and minor sectors
- Calculate area of sectors using the formula

In groups, learners are guided to:
- Draw a circle and mark a clock face
- Identify sectors formed by clock hands
- Derive formula: Area = (θ/360) × πr²
- Calculate areas of sectors with different angles
- Use digital devices to watch videos on sectors

How do we find the area of a sector?

- Master Mathematics Grade 9 pg. 85
- Compasses and rulers
- Protractors
- Digital devices
- Internet access
- Compasses
- Rulers
- Calculators
- Graph paper

- Observation - Oral questions - Written assignments

Measurements

Area - Surface area of cones
Area - Surface area of spheres and hemispheres

By the end of the lesson, the learner should be able to:
- Define a cone and identify its parts
- Derive the formula for curved surface area
- Calculate surface area of solid cones

In groups, learners are guided to:
- Draw and cut a circle from manila paper
- Divide into two parts and fold to make a cone
- Identify slant height and radius
- Derive formula: πrl for curved surface
- Calculate total surface area: πrl + πr²
- Solve practical problems

How do we find the surface area of a cone?

- Master Mathematics Grade 9 pg. 85
- Manila paper
- Scissors
- Compasses and rulers
- Reference materials
- Spherical balls
- Rectangular paper
- Rulers
- Calculators

- Observation - Oral questions - Written assignments

Measurements

Volume - Volume of triangular prisms
Volume - Volume of rectangular prisms

By the end of the lesson, the learner should be able to:
- Define a prism
- Identify uniform cross-sections
- Calculate volume of triangular prisms

In groups, learners are guided to:
- Make a triangular prism using locally available materials
- Place prism vertically and fill with sand
- Identify the cross-section
- Apply formula: V = Area of cross-section × length
- Calculate area of triangular cross-section
- Multiply by length to get volume

How do we find the volume of a prism?

- Master Mathematics Grade 9 pg. 102
- Straws and paper
- Sand or soil
- Measuring tools
- Reference books
- Cuboid models
- Calculators
- Charts
- Reference materials

- Observation - Oral questions - Written assignments

Measurements

Volume - Volume of square-based pyramids
Volume - Volume of rectangular-based pyramids

By the end of the lesson, the learner should be able to:
- Define a right pyramid
- Relate pyramid volume to cube volume
- Calculate volume of square-based pyramids

In groups, learners are guided to:
- Model a cube and pyramid with same base and height
- Fill pyramid with soil and transfer to cube
- Observe that pyramid is ⅓ of cube
- Apply formula: V = ⅓ × base area × height
- Calculate volumes of square-based pyramids

How do we find the volume of a pyramid?

- Master Mathematics Grade 9 pg. 102
- Modeling materials
- Soil or sand
- Rulers
- Calculators
- Pyramid models
- Graph paper
- Reference books

- Observation - Oral questions - Written assignments

Measurements

Volume - Volume of triangular-based pyramids
Volume - Introduction to volume of cones

By the end of the lesson, the learner should be able to:
- Calculate area of triangular bases
- Apply Pythagoras theorem where necessary
- Calculate volume of triangular-based pyramids

In groups, learners are guided to:
- Calculate area of triangular base (using ½bh)
- For equilateral triangles, use Pythagoras to find height
- Apply formula: V = ⅓ × (½bh) × H
- Solve problems with different triangular bases

How do we find volume of triangular pyramids?

- Master Mathematics Grade 9 pg. 102
- Triangular pyramid models
- Rulers
- Calculators
- Charts
- Cone and cylinder models
- Water
- Digital devices
- Internet access

- Observation - Oral questions - Written assignments

Measurements

Volume - Calculating volume of cones
Volume - Volume of frustums of pyramids

By the end of the lesson, the learner should be able to:
- Apply the cone volume formula
- Use Pythagoras theorem to find missing dimensions
- Calculate volumes of cones with different measurements

In groups, learners are guided to:
- Apply formula: V = ⅓πr²h
- Use Pythagoras to find radius when given slant height
- Use Pythagoras to find height when given slant height
- Solve practical problems (birthday caps, funnels)

How do we calculate the volume of a cone?

- Master Mathematics Grade 9 pg. 102
- Cone models
- Calculators
- Graph paper
- Reference materials
- Pyramid models
- Cutting tools
- Rulers

- Observation - Oral questions - Written assignments

Measurements

Volume - Volume of frustums of cones

By the end of the lesson, the learner should be able to:
- Identify frustums of cones
- Apply the frustum concept to cones
- Calculate volume of frustums of cones

In groups, learners are guided to:
- Identify frustums with circular bases
- Calculate volume of original cone
- Calculate volume of small cone cut off
- Subtract to get volume of frustum
- Solve real-life problems (lampshades, buckets)

How do we calculate the volume of a frustum of a cone?

- Master Mathematics Grade 9 pg. 102
- Cone models
- Frustum examples
- Calculators
- Reference books

- Observation - Oral questions - Written assignments

Measurements

Volume - Volume of spheres
Volume - Volume of hemispheres and applications

By the end of the lesson, the learner should be able to:
- Relate sphere volume to cone volume
- Derive the formula for volume of a sphere
- Calculate volumes of spheres

In groups, learners are guided to:
- Select hollow spherical object
- Model cone with same radius and height 2r
- Fill cone and transfer to sphere
- Observe that 2 cones fill the sphere
- Derive formula: V = 4/3πr³
- Calculate volumes with different radii

How do we find the volume of a sphere?

- Master Mathematics Grade 9 pg. 102
- Hollow spheres
- Cone models
- Water or soil
- Calculators
- Hemisphere models
- Real objects
- Reference materials

- Observation - Oral questions - Written tests

Measurements

Mass, Volume, Weight and Density - Conversion of units of mass
Mass, Volume, Weight and Density - More practice on mass conversions

By the end of the lesson, the learner should be able to:
- Define mass and state its SI unit
- Identify different units of mass
- Convert between different units of mass

In groups, learners are guided to:
- Use balance to measure mass of objects
- Record masses in grams
- Study conversion table for mass units
- Convert between kg, g, mg, tonnes, etc.
- Apply conversions to real situations

How do we convert between different units of mass?

- Master Mathematics Grade 9 pg. 111
- Weighing balances
- Various objects
- Conversion charts
- Calculators
- Conversion tables
- Real-world examples
- Reference books

- Observation - Oral questions - Written tests

Measurements

Mass, Volume, Weight and Density - Relationship between mass and weight
Mass, Volume, Weight and Density - Calculating mass and gravity

By the end of the lesson, the learner should be able to:
- Define weight and state its SI unit
- Distinguish between mass and weight
- Calculate weight from mass using gravity

In groups, learners are guided to:
- Study spring balance showing both mass and weight
- Observe relationship: 1 kg = 10 N
- Apply formula: Weight = mass × gravity
- Calculate weights of various objects
- Understand that mass is constant but weight varies

What is the difference between mass and weight?

- Master Mathematics Grade 9 pg. 111
- Spring balances
- Various objects
- Charts
- Calculators
- Charts showing planetary data
- Reference materials
- Digital devices

- Observation - Oral questions - Written tests

Measurements

Mass, Volume, Weight and Density - Introduction to density
Mass, Volume, Weight and Density - Calculating density, mass and volume

By the end of the lesson, the learner should be able to:
- Define density
- State units of density
- Relate mass, volume and density

In groups, learners are guided to:
- Weigh empty container
- Measure volume of water using measuring cylinder
- Weigh container with water
- Calculate mass of water
- Divide mass by volume to get density
- Apply formula: Density = Mass/Volume

What is density?

- Master Mathematics Grade 9 pg. 111
- Weighing balances
- Measuring cylinders
- Water
- Containers
- Calculators
- Charts with formulas
- Various solid objects
- Reference books

- Observation - Oral questions - Written tests

Measurements

Mass, Volume, Weight and Density - Applications of density
Time, Distance and Speed - Working out speed in km/h and m/s

By the end of the lesson, the learner should be able to:
- Apply density to identify materials
- Determine if objects will float or sink
- Solve real-life problems using density

In groups, learners are guided to:
- Compare calculated density with known values
- Identify minerals (e.g., diamond) using density
- Determine if objects float (density < 1 g/cm³)
- Apply to quality control (milk, water)
- Solve problems involving balloons, anchors

How is density used in real life?

- Master Mathematics Grade 9 pg. 111
- Density tables
- Calculators
- Real-world scenarios
- Reference materials
- Master Mathematics Grade 9 pg. 117
- Stopwatches
- Tape measures
- Open field
- Conversion charts

- Observation - Oral questions - Written tests

Measurements

Time, Distance and Speed - Calculating distance and time from speed
Time, Distance and Speed - Working out average speed

By the end of the lesson, the learner should be able to:
- Rearrange speed formula to find distance
- Rearrange speed formula to find time
- Solve problems involving speed, distance and time
- Apply to real-life situations

In groups, learners are guided to:
- Apply formula: Distance = Speed × Time
- Apply formula: Time = Distance/Speed
- Solve problems with different units
- Apply to journeys, races, train travel
- Work with Madaraka Express train problems
- Calculate distances covered at given speeds
- Calculate time taken for journeys

How do we calculate distance and time from speed?

- Master Mathematics Grade 9 pg. 117
- Calculators
- Formula charts
- Real-world examples
- Reference materials
- Field with marked points
- Stopwatches
- Reference books

- Observation - Oral questions - Written tests

Measurements

Time, Distance and Speed - Determining velocity
Time, Distance and Speed - Working out acceleration

By the end of the lesson, the learner should be able to:
- Define velocity
- Distinguish between speed and velocity
- Calculate velocity with direction
- Appreciate the importance of direction in velocity

In groups, learners are guided to:
- Define velocity as speed in a given direction
- Identify that velocity includes direction
- Calculate velocity for objects moving in straight lines
- Understand that velocity can be positive or negative
- Understand that same speed in opposite directions means different velocities
- Apply to real situations involving directional movement

What is the difference between speed and velocity?

- Master Mathematics Grade 9 pg. 117
- Diagrams showing direction
- Calculators
- Charts
- Reference materials
- Field for activity
- Stopwatches
- Measuring tools
- Formula charts

- Observation - Oral questions - Written tests

Measurements

Time, Distance and Speed - Deceleration and applications
Time, Distance and Speed - Identifying longitudes on the globe

By the end of the lesson, the learner should be able to:
- Define deceleration (retardation)
- Calculate deceleration
- Distinguish between acceleration and deceleration
- Solve problems involving both acceleration and deceleration
- Appreciate safety implications

In groups, learners are guided to:
- Define deceleration as negative acceleration
- Calculate when final velocity is less than initial velocity
- Apply to vehicles slowing down, braking
- Apply to matatus crossing speed bumps
- Understand safety implications of deceleration
- Calculate final velocity given acceleration and time
- Solve problems on cars, buses, gazelles
- Discuss importance of controlled deceleration for safety

What is deceleration and why is it important for safety?

- Master Mathematics Grade 9 pg. 117
- Calculators
- Road safety materials
- Charts
- Reference materials
- Globes
- Atlases
- World maps

- Observation - Oral questions - Written tests

Measurements

Time, Distance and Speed - Relating longitudes to time
Time, Distance and Speed - Calculating time differences between places

By the end of the lesson, the learner should be able to:
- Explain relationship between longitudes and time
- State that Earth rotates 360° in 24 hours
- Calculate that 1° = 4 minutes
- Understand time zones and GMT

In groups, learners are guided to:
- Understand Earth rotates 360° in 24 hours
- Calculate: 360° = 24 hours = 1440 minutes
- Therefore: 1° = 4 minutes
- Identify time zones on world map
- Understand GMT (Greenwich Mean Time)
- Learn that places East of Greenwich are ahead in time
- Learn that places West of Greenwich are behind in time
- Use digital devices to check time zones

How are longitudes related to time?

- Master Mathematics Grade 9 pg. 117
- Globes
- Time zone maps
- Calculators
- Digital devices
- Atlases
- Time zone charts
- Reference books

- Observation - Oral questions - Written tests

Measurements

Time, Distance and Speed - Determining local time of places along different longitudes

By the end of the lesson, the learner should be able to:
- Calculate local time when given GMT or another place's time
- Add or subtract time differences appropriately
- Account for date changes
- Solve complex time zone problems
- Apply knowledge to real-life situations

In groups, learners are guided to:
- Calculate time difference from longitude difference
- Add time if place is East of reference point (ahead)
- Subtract time if place is West of reference point (behind)
- Account for date changes when crossing midnight
- Solve problems with GMT as reference
- Solve problems with other places as reference
- Apply to phone calls, soccer matches, travel planning
- Work backwards to find longitude from time difference
- Determine whether places are East or West from time relationships

How do we find local time at different longitudes?

- Master Mathematics Grade 9 pg. 117
- World maps
- Calculators
- Time zone references
- Atlases
- Real-world scenarios

- Observation - Oral questions - Written tests - Problem-solving tasks

Measurements

Money - Identifying currencies of different countries
Money - Converting foreign currency to Kenyan shillings

By the end of the lesson, the learner should be able to:
- Identify currencies used in different countries
- State the Kenyan currency and its abbreviation
- Match countries with their currencies
- Appreciate diversity in world currencies

In groups, learners are guided to:
- Use digital devices to search for pictures of currencies
- Identify currencies of Britain, Uganda, Tanzania, USA, Rwanda, South Africa
- Make a collage of currencies from African countries
- Complete tables matching countries with their currencies
- Study Kenya shilling and its subdivision into cents
- Discuss the importance of different currencies

What currencies are used in different countries?

- Master Mathematics Grade 9 pg. 131
- Digital devices
- Internet access
- Pictures of currencies
- Atlases
- Reference materials
- Currency conversion tables
- Calculators
- Charts

- Observation - Oral questions - Written assignments - Project work

Measurements

Money - Converting Kenyan shillings to foreign currency and buying/selling rates
Money - Export duty on goods

By the end of the lesson, the learner should be able to:
- Convert Kenyan shillings to foreign currencies
- Distinguish between buying and selling rates
- Apply correct rates when converting currency
- Solve multi-step currency problems

In groups, learners are guided to:
- Convert Ksh to Ugandan shillings, Sterling pounds, Japanese Yen
- Study Table 3.5.2 showing buying and selling rates
- Understand that banks buy at lower rate, sell at higher rate
- Learn when to use buying rate (foreign to Ksh)
- Learn when to use selling rate (Ksh to foreign)
- Solve tourist problems with multiple conversions
- Visit commercial banks or Forex Bureaus

Why do buying and selling rates differ?

- Master Mathematics Grade 9 pg. 131
- Exchange rate tables
- Calculators
- Real-world scenarios
- Reference books
- Examples of export goods
- Charts
- Reference materials

- Observation - Oral questions - Written assignments

Measurements

Money - Import duty on goods
Money - Excise duty and Value Added Tax (VAT)

By the end of the lesson, the learner should be able to:
- Define import and import duty
- Calculate customs value of imported goods
- Calculate import duty on goods
- Apply knowledge to real-life situations

In groups, learners are guided to:
- Discuss goods imported into Kenya
- Learn about Kenya Revenue Authority (KRA)
- Calculate customs value: Cost + Insurance + Freight
- Apply formula: Import duty = Tax rate × Customs value
- Solve problems on vehicles, electronics, tractors, phones
- Discuss ways to reduce imports
- Understand importance of local production

What is import duty and how is it calculated?

- Master Mathematics Grade 9 pg. 131
- Calculators
- Import duty examples
- Charts
- Reference books
- Digital devices
- ETR receipts
- Tax rate tables
- Reference materials

- Observation - Oral questions - Written assignments

Measurements

Money - Combined duties and taxes on imported goods
Approximations and Errors - Approximating quantities in measurements

By the end of the lesson, the learner should be able to:
- Calculate multiple taxes on imported goods
- Apply import duty, excise duty, and VAT sequentially
- Solve complex problems involving all taxes
- Appreciate the cumulative effect of taxes

In groups, learners are guided to:
- Calculate import duty first
- Calculate excise value: Customs value + Import duty
- Calculate excise duty on excise value
- Calculate VAT value: Customs value + Import duty + Excise duty
- Calculate VAT on VAT value
- Apply to vehicles, electronics, cement, phones
- Solve comprehensive taxation problems
- Work backwards to find customs value

How do we calculate total taxes on imported goods?

- Master Mathematics Grade 9 pg. 131
- Calculators
- Comprehensive examples
- Charts showing tax flow
- Reference materials
- Master Mathematics Grade 9 pg. 146
- Tape measures
- Various objects to measure
- Containers for capacity

- Observation - Oral questions - Written assignments

Measurements

Approximations and Errors - Determining errors using estimations and actual measurements
Approximations and Errors - Calculating percentage error

By the end of the lesson, the learner should be able to:
- Define error in measurement
- Calculate error using approximated and actual values
- Distinguish between positive and negative errors
- Appreciate the importance of accuracy

In groups, learners are guided to:
- Fill 500 ml bottle and measure actual volume
- Calculate difference between labeled and actual values
- Apply formula: Error = Approximated value - Actual value
- Work with errors in mass, length, volume, time
- Complete tables showing actual, estimated values and errors
- Apply to bread packages, water bottles, cement bags
- Discuss integrity in measurements

What is error and how do we calculate it?

- Master Mathematics Grade 9 pg. 146
- Measuring cylinders
- Water bottles
- Weighing scales
- Calculators
- Reference materials
- Tape measures
- Open ground for activities
- Reference books

- Observation - Oral questions - Written assignments

Measurements

Approximations and Errors - Percentage error in real-life situations
Approximations and Errors - Complex applications and problem-solving

By the end of the lesson, the learner should be able to:
- Apply percentage error to real-life situations
- Calculate errors in various contexts
- Analyze significance of errors
- Show integrity when making approximations

In groups, learners are guided to:
- Calculate percentage errors in electoral voting estimates
- Work on football match attendance approximations
- Solve problems on road length estimates
- Apply to temperature recordings
- Calculate errors in land plot sizes
- Work on age recording errors
- Discuss consequences of errors in planning

Why are accurate approximations important in real life?

- Master Mathematics Grade 9 pg. 146
- Calculators
- Real-world scenarios
- Case studies
- Reference materials
- Complex scenarios
- Charts
- Reference books
- Real-world case studies

- Observation - Oral questions - Written assignments

4.0 Geometry

4.1 Coordinates and Graphs - Plotting points on a Cartesian plane
4.1 Coordinates and Graphs - Drawing straight line graphs given equations
4.1 Coordinates and Graphs - Drawing parallel lines on the Cartesian plane
4.1 Coordinates and Graphs - Relating gradients of parallel lines

By the end of the lesson, the learner should be able to:
- Define a Cartesian plane and identify its components
- Plot points accurately on a Cartesian plane using coordinates
- Show interest in learning about coordinate geometry

The learner is guided to:
- Discuss with friends what they remember about plotting points on a Cartesian plane
- Draw a Cartesian plane in their graph book
- Mark the points where given coordinates lie
- Discuss and compare their work with other learners

How do we locate points on a Cartesian plane?

- Master Mathematics Grade 9 pg. 152
- Graph papers/squared books
- Rulers
- Pencils
- Digital devices
- Master Mathematics Grade 9 pg. 154
- Graph papers
- Mathematical tables
- Master Mathematics Grade 9 pg. 156
- Set squares
- Master Mathematics Grade 9 pg. 158
- Calculators

- Observation - Oral questions - Written assignments

4.0 Geometry

4.1 Coordinates and Graphs - Drawing perpendicular lines on the Cartesian plane
4.1 Coordinates and Graphs - Relating gradients of perpendicular lines and applications
4.2 Scale Drawing - Compass bearing
4.2 Scale Drawing - True bearings

By the end of the lesson, the learner should be able to:
- Explain the meaning of perpendicular lines
- Draw and measure angles between perpendicular lines accurately
- Show interest in recognizing perpendicular lines from their graphs

The learner is guided to:
- Draw straight lines on the same Cartesian plane
- Identify the point where the two lines intersect
- Measure the angle between the two lines at the point of intersection
- Verify that perpendicular lines intersect at 90°

How do we identify perpendicular lines on a graph?

- Master Mathematics Grade 9 pg. 160
- Graph papers
- Protractors
- Rulers
- Set squares
- Master Mathematics Grade 9 pg. 162
- Calculators
- Real-life graph examples
- Master Mathematics Grade 9 pg. 166
- Pair of compasses
- Charts showing compass directions
- Master Mathematics Grade 9 pg. 169
- Compasses
- Map samples

- Observation - Class activities - Written tests

4.0 Geometry

4.2 Scale Drawing - Determining the bearing of one point from another (1)
4.2 Scale Drawing - Determining the bearing of one point from another (2)

By the end of the lesson, the learner should be able to:
- Describe the steps for determining bearings between two points
- Measure bearings accurately using a protractor
- Show interest in finding bearings of different places

The learner is guided to:
- Join two points using a straight line
- Locate the point from which bearing is determined
- Draw a North line at that point
- Measure the required angle clockwise from North

How do we find the bearing of one place from another?

- Master Mathematics Grade 9 pg. 171
- Protractors
- Rulers
- Pencils
- Graph papers
- Atlas/Maps of Kenya
- Digital devices

- Observation - Oral questions - Written assignments

4.0 Geometry

4.2 Scale Drawing - Locating a point using bearing and distance (1)
4.2 Scale Drawing - Locating a point using bearing and distance (2)

By the end of the lesson, the learner should be able to:
- Explain how to choose appropriate scales for scale drawings
- Convert actual distances to scale lengths accurately
- Show interest in representing actual distances on paper

The learner is guided to:
- Draw sketch diagrams showing relative positions
- Choose suitable scales
- Convert actual distances to scale lengths
- Mark North lines and measure angles

How do we represent actual distances on paper?

- Master Mathematics Grade 9 pg. 173
- Rulers
- Protractors
- Compasses
- Plain papers
- Graph papers

- Observation - Written assignments

4.0 Geometry

4.2 Scale Drawing - Identifying angles of elevation (1)
4.2 Scale Drawing - Determining angles of elevation (2)

By the end of the lesson, the learner should be able to:
- Define angle of elevation
- Identify and sketch right-angled triangles showing angles of elevation
- Develop interest in recognizing situations involving angles of elevation

The learner is guided to:
- Observe objects above eye level
- Identify the angle through which eyes are raised
- Sketch right-angled triangles formed
- Label the angle of elevation correctly

What is an angle of elevation?

- Master Mathematics Grade 9 pg. 175
- Protractors
- Rulers
- Pictures showing elevation
- Models
- Graph papers
- Calculators

- Observation - Oral questions

4.0 Geometry

4.2 Scale Drawing - Identifying angles of depression (1)
4.2 Scale Drawing - Determining angles of depression (2)

By the end of the lesson, the learner should be able to:
- Define angle of depression
- Identify and sketch situations involving angles of depression
- Show interest in distinguishing between angles of elevation and depression

The learner is guided to:
- Stand at elevated positions and observe objects below
- Identify the angle through which eyes are lowered
- Sketch right-angled triangles formed
- Label the angle of depression correctly

How is angle of depression different from angle of elevation?

- Master Mathematics Grade 9 pg. 178
- Protractors
- Rulers
- Pictures showing depression
- Models
- Graph papers
- Calculators

- Observation - Oral questions

4.0 Geometry

4.2 Scale Drawing - Application in simple surveying - Triangulation (1)
4.2 Scale Drawing - Application in simple surveying - Triangulation (2)

By the end of the lesson, the learner should be able to:
- Explain the concept of triangulation in surveying
- Identify baselines and offsets and draw diagrams using triangulation method
- Develop interest in using triangulation for surveying

The learner is guided to:
- Trace irregular shapes to be surveyed
- Enclose the shape with a triangle
- Identify and measure baselines
- Draw perpendicular offsets to the baselines

What is triangulation and how is it used in surveying?

- Master Mathematics Grade 9 pg. 180
- Rulers
- Set squares
- Compasses
- Plain papers
- Meter rules
- Strings
- Pegs
- Field books

- Observation - Class activities

4.0 Geometry

4.2 Scale Drawing - Application in simple surveying - Transverse survey (1)

By the end of the lesson, the learner should be able to:
- Explain transverse survey method
- Identify baselines and draw offsets on either side accurately
- Show interest in understanding different surveying methods

The learner is guided to:
- Draw baselines at the middle of areas to be surveyed
- Draw offsets perpendicular to baselines on both sides
- Measure lengths of offsets from baselines
- Record measurements in tables

How is transverse survey different from triangulation?

- Master Mathematics Grade 9 pg. 180
- Rulers
- Set squares
- Plain papers
- Field books

- Observation - Oral questions

4.0 Geometry

4.2 Scale Drawing - Application in simple surveying - Transverse survey (2)
4.2 Scale Drawing - Surveying using bearings and distances

By the end of the lesson, the learner should be able to:
- Describe the process of completing field books for transverse surveys
- Draw scale maps from transverse survey data
- Appreciate using transverse survey method for road reserves

The learner is guided to:
- Complete field book recordings
- Use appropriate scales to draw maps
- Join offset points to show boundaries
- Compare their work with other members

When do we use transverse survey method?

- Master Mathematics Grade 9 pg. 180
- Rulers
- Pencils
- Graph papers
- Field books
- Protractors
- Compasses

- Written assignments - Practical activities

4.0 Geometry

4.3 Similarity and Enlargement - Similar figures
4.3 Similarity and Enlargement - Properties of similar figures (1)

By the end of the lesson, the learner should be able to:
- Define similar figures
- Identify and sort similar figures from collections of objects
- Show interest in recognizing similar figures in the environment

The learner is guided to:
- Collect different objects from the environment
- Sort objects according to similarity
- Discuss criteria used for sorting
- Identify pairs of similar figures from given diagrams

What makes two figures similar?

- Master Mathematics Grade 9 pg. 185
- Various objects
- Cut-outs of shapes
- Charts
- Models
- Master Mathematics Grade 9 pg. 186
- Rulers
- Tracing papers
- Calculators
- Pencils

- Observation - Oral questions

4.0 Geometry

4.3 Similarity and Enlargement - Properties of similar figures (2)
4.3 Similarity and Enlargement - Drawing similar figures

By the end of the lesson, the learner should be able to:
- Identify that corresponding angles of similar figures are equal
- Use properties to determine unknown sides and angles
- Develop interest in applying properties of similar figures

The learner is guided to:
- Measure corresponding angles of similar figures
- Observe that corresponding angles are equal
- Use ratio of sides to find unknown lengths
- Solve problems involving similar figures

How do we use properties of similar figures?

- Master Mathematics Grade 9 pg. 186
- Protractors
- Rulers
- Calculators
- Practice worksheets
- Master Mathematics Grade 9 pg. 189
- Compasses
- Plain papers

- Written tests - Oral questions

4.0 Geometry

4.3 Similarity and Enlargement - Determining properties of enlargement
4.3 Similarity and Enlargement - Positive scale factor (1)

By the end of the lesson, the learner should be able to:
- Define centre of enlargement and scale factor
- Locate the centre of enlargement and determine scale factor
- Appreciate that enlargements produce similar figures

The learner is guided to:
- Join corresponding points of objects and images
- Locate the centre where lines meet
- Measure distances from centre to object and image
- Calculate the scale factor

What is the relationship between object and image in enlargement?

- Master Mathematics Grade 9 pg. 190
- Rulers
- Compasses
- Tracing papers
- Models
- Master Mathematics Grade 9 pg. 192
- Graph papers
- Pencils

- Class activities - Written assignments

4.0 Geometry

4.3 Similarity and Enlargement - Positive scale factor (2)
4.3 Similarity and Enlargement - Negative scale factor (1)

By the end of the lesson, the learner should be able to:
- Describe what happens when scale factor is between 0 and 1
- Draw enlargements with fractional scale factors accurately
- Appreciate comparing enlargements with different positive scale factors

The learner is guided to:
- Draw enlargements with fractional scale factors
- Observe that images are smaller than objects
- Note that object and image remain upright
- Practice with various positive scale factors

What happens when the scale factor is between 0 and 1?

- Master Mathematics Grade 9 pg. 192
- Rulers
- Compasses
- Plain papers
- Models
- Master Mathematics Grade 9 pg. 196
- Graph papers
- Tracing papers

- Class activities - Written assignments

4.0 Geometry

4.3 Similarity and Enlargement - Negative scale factor (2)
4.3 Similarity and Enlargement - Enlargement on the Cartesian plane (1)

By the end of the lesson, the learner should be able to:
- Explain the process of determining negative scale factors
- Locate centres of enlargement and apply negative scale factors to various figures
- Appreciate solving problems involving negative enlargements

The learner is guided to:
- Join corresponding vertices to locate centres
- Calculate scale factors from measurements
- Draw enlargements of different shapes with negative scale factors
- Solve problems involving negative enlargements

How do we work with negative scale factors?

- Master Mathematics Grade 9 pg. 196
- Rulers
- Compasses
- Plain papers
- Calculators
- Master Mathematics Grade 9 pg. 198
- Graph papers
- Pencils

- Written tests - Class activities

4.0 Geometry

4.3 Similarity and Enlargement - Enlargement on the Cartesian plane (2)
4.3 Similarity and Enlargement - Linear scale factor of similar figures (1)

By the end of the lesson, the learner should be able to:
- Describe the process of enlarging figures with centre not at origin
- Determine coordinates of images after enlargement and solve related problems
- Appreciate applying both positive and negative scale factors on Cartesian plane

The learner is guided to:
- Plot figures with given vertices
- Enlarge with centres at various points
- Determine image coordinates
- Apply both positive and negative scale factors

What happens when the centre is not at the origin?

- Master Mathematics Grade 9 pg. 198
- Graph papers
- Rulers
- Calculators
- Digital devices
- Master Mathematics Grade 9 pg. 200
- Similar objects
- Models

- Written tests - Class activities

4.0 Geometry

4.3 Similarity and Enlargement - Linear scale factor of similar figures (2)
4.4 Trigonometry - Angles and sides of right-angled triangles

By the end of the lesson, the learner should be able to:
- Explain applications of linear scale factor in real-life situations
- Solve problems involving scale models and drawings
- Appreciate use of similarity in architecture and mapping

The learner is guided to:
- Work with scale drawings and models
- Determine actual dimensions from scale drawings
- Calculate linear scale factors from given information
- Discuss applications in architecture and mapping

How is linear scale factor used in real life?

- Master Mathematics Grade 9 pg. 200
- Maps
- Scale models
- Calculators
- Real objects
- Master Mathematics Grade 9 pg. 205
- Rulers
- Set squares
- Models of triangles
- Charts

- Written assignments - Written tests

4.0 Geometry

4.4 Trigonometry - Tangent ratio and tables of tangents
4.4 Trigonometry - Sine and cosine ratios, tables of sines and cosines

By the end of the lesson, the learner should be able to:
- Define tangent of an angle as opposite/adjacent
- Calculate tangent ratios from right-angled triangles and read from tables
- Appreciate that tangent ratio is constant for a given angle

The learner is guided to:
- Work out ratios of opposite to adjacent sides
- Recognize that the ratio is constant for a given angle
- Define tangent as opposite/adjacent
- Read tangent values from tables

What is the tangent of an angle?

- Master Mathematics Grade 9 pg. 207
- Mathematical tables
- Rulers
- Calculators
- Right-angled triangles
- Master Mathematics Grade 9 pg. 211
- Models

- Class activities - Written tests

4.0 Geometry

4.4 Trigonometry - Using calculators and applications of trigonometric ratios

By the end of the lesson, the learner should be able to:
- Explain how to use calculators to find trigonometric ratios
- Apply trigonometric ratios to calculate unknown sides and angles
- Appreciate using trigonometry to solve real-life problems

The learner is guided to:
- Use calculator buttons for sin, cos, tan
- Find inverse trigonometric ratios
- Calculate unknown lengths in right-angled triangles
- Solve problems involving heights, distances and angles

How do we use trigonometry to solve real-life problems?

- Master Mathematics Grade 9 pg. 217
- Scientific calculators
- Rulers
- Protractors
- Real-life problem scenarios

- Written tests - Practical activities